Automated Identification of Plywood Using Embedded Inkjet-Printed Passive UHF RFID Tags

Abstract

The use of passive ultra high-frequency (UHF) radio frequency identification (RFID) integrated into plywood boards is proposed to enable the identification and tracking of individual plywood boards and end products of plywood. For the first time, tags are embeddable inside plywood by direct inkjet-printing tag antennas on pure birch veneer. The use of passive UHF RFID technology in the applications of plywood industry is discussed, two tag antenna designs for plywood are presented and the tag fabrication procedures are described. Furthermore, results from tag performance measurements performed in the authentic application environment as well as in anechoic conditions are presented and discussed. Measurements show that tags printed on veneer and embedded inside 2 mm thick plywood board exhibited theoretical read ranges from 7.9 to 10.1 meters. The read ranges obtained meet the demands of the plywood industry and offer reliable identification even in challenging environments.Note to Practitioners-The use of integrated UHF RFID technology embedded inside plywood could bring significant benefits to the plywood industry. At the moment, identification and tracking are done manually or by using bar codes on large shipments of plywood. Manual identification can lead to misreads and external bar codes are easily detached or damaged. In this paper, we propose a solution to directly inkjet-print RFID tags on veneer. After printing, they can be embedded inside plywood. As a result, individual plywood boards are identifiable and traceable during their whole lifetime, even in their end product form. This paper discusses the benefits and challenges of passive UHF RFID technology in the plywood industry, explains the tag fabrication procedures and presents the measurement results of plywood-embedded tags. Results show that the tags are readable from several meters, even inside thick plywood boards. Thus, embedded RFID technology could be utilized by the industry as well as by the end users of plywood as an efficient and reliable automated identification method for plywood boards and plywood-made products.Index Terms-Plywood industry, radio frequency identification (RFID), inkjet.

Experimental Study on Brush-Painted Metallic Nanoparticle UHF RFID Tags on Wood Substrates

“…In the direction of the grain, such variations are low, whereas against the grain, variations are significant. In fact, in our previous study, it was found that RFID tag antennas inkjet-printed on wood veneer only in one direction did not function even with several layers of conductive ink, and that antennas that had the antenna geometry printed along the grain showed the best performance [3]. This was also discovered in our preliminary tests; the conductivity of the antenna brushed against the grain was significantly lower than conductivity of the antenna brushed along the grain.…”

“…In our previous study, inkjet-printed and heat-sintered silver nanoparticle UHF RFID tags on wood veneer, with quite similar tag antenna geometry, achieved peak read ranges of 6.5 m and read ranges of over 2 m throughout the global UHF RFID band [3]. Thus, these brush-painted antennas offer an alternative to inkjet-printed antennas on wood substrates.…”

“…The measured realized gain of the tag antenna is analyzed using the path-loss measurement data from the measurement unit. Realized gain takes into account the antenna-IC impedance matching and can be calculated as (3) where is the tag IC sensitivity, and and are as in (2).…”

“…The information can be restored throughout the life cycle from the factory to the end-user. RFID tags have already been applied to wood logs for timber supply chain [2] and for plywood boards [3]. A comprehensive introduction to passive UHF RFID systems is provided in [4].…”

“…Prototype RFID tags have been printed on wood substrate by screen printing [7] and by inkjet printing [3], using silver particle inks and heat sintering. These tags have showed good performance on wood substrate, but their manufacturing has required several printed layers [3], [7], more than one printing-sintering rounds with different printing directions [3], and long sintering times in the oven (20-60 min) [3], [7]. In addition, in the case of copper inks, heat sintering is problematic because of nonconductive copper oxide.…”